Starting and stopping mechanism



Dec. 31, 1940. R. N. SANDBERG STARTING AND STOPPING MECHANISM Filed Oct. 26, 1957 KM/WW lvvf/v TUE:

I DA) 3mm Patented ec. 31, 1940 STATES STARTING AND STOPPING MECHANISM Robert N. Sandberg, Beverly, Mass, assignor to United Shoe Machinery Corporation, Borough of Flemington, N. J., a corporation of New Jersey Application October 26, 1937, Serial No. 171,179

3 Claims.

This invention relates to starting and stopping mechanisms and is herein illustrated in a form designed to fulfill certain requirements in a trimming machine more fully illustrated and described in a copending application for United States Letters Patent Serial No. 172,115, filed November 1, 1937, in the name of Vernon H. Meyer. The organization illustrated in the aforesaid application includes a. rotary disk cutter and an abrading wheel by which its cutting edge may be sharpened without interrupting its rotation. The rotation of the cutter is or may be continuous throughout long periods of use, but since the use of the abrading wheel is required only for very short periods as the cutting edge becomes dull, continuous rotation of the abrading wheel is not required.

Accordingly, an object of the present invention is to provide improved starting andstoppingmechanisms suitable for conditions such as those above mentioned. To this end, the illustrated machine is provided with an improved combination comprising an abrading wheel, a manually movable operating member by which it may be shifted to and from the cutter to be sharpened thereby, a clutch for'transmitting rotation to the abrading wheel when it is shifted to its operative position, and improved means for controlling the clutch. These elements are so organized that the abrading wheel remains normally out of rotation and a short distance away from the cutter, and the simple act of moving the operating lever to shift the abrading wheel to its operative position is effective also to render the clutch operable to set up rotation of the abrading wheel without afiecting the manual control or the pressure with which the user moves the abrading wheel into contact with the cutter.

Other novel features of the invention are here- 40 inafter described and claimed and are illustrated in the accompanying drawing, in which Fig. 1 is a vertical section, partly in elevation, of a starting and stopping mechanism embodying the present invention in a construction designed for a machine more fully illustrated and described in the aforesaid Meyer application; and

Fig. 2 is a horizontal section of the structure intersected by line IIII of Fig. 1.

For convenience in comparing the drawing of this application with the drawing of the aforesaid Meyer application, the individual parts of the structure are identified by the same reference numerals in both applications.

For purposes of the present description, the 55 work to be abraded is a saucer-shaped disk or annulus of pressed sheet steel constituting a rotary cutter H). A circular central portion is punched out of this member to provide for mounting it in concentric relation to a vertical rotary spindle II by which it is carried. The outer margin of the cutter is frusto-conical and its rim is sharpened to provide an endless cutting edge l2 that lies in a plane at right angles to the axis of the spindle. A flange 13 formed on or affixed to the spindle l I provides an annular seat against which the inner margin of the cutter may be clamped by a detachable clamping disk I 4, the flange I 3 being provided with a concentric shoulder l5 adapted to fit closely in the central opening in the cutter. A nut l6 screwed on the upper end of the spindle bears against the disk M to apply clamping pressure thereto.

The spindle H is mounted in ball-bearings IT, I! secured in sockets formed in a frame I8, the parts being so organized that the upper bearing l7 serves also as a thrust-bearing. A receiving pulley I9 aiiixed to the spindle H is driven by a belt 28 that serves also, under certain conditions, to drive a rotary abrading wheel ill by which the cutting edge 12 may be sharpened without interrupting its rotation. Accordingly, the belt 20 passes around a pulley 22 that is initially free to rotate without imparting rotation to the abrading wheel. The belt 2! also runs on idlers (not shown) and on a driving pulley (not shown).

The abrading wheel 2| underlies a segment of the cutter l0 and normally remains at the level pictured in Fig. 1 where its upper surface (operating surface) is a considerable distance below the plane of the bottom of the cutter. Theabrading wheel is initially supported in this position by a boss 15 formed on a bracket 8|. The abrading wheel is secured to the upper end of a virtually vertical spindle 13 journaled in an upper bushing and in a lower bushing 14. The bushing 55 is tightly secured in the boss 15 but the bushing 14, although arranged to extend through the lower portion of the bracket BI, is capable of limited ,movement up and down along the axis of the f spindle journaled therein. To secure the abrading wheel to the spindle, the latter is provided with a flange H, a detachable clamping disk 18 and a clamping nut 19 by which the web of the abrading wheel may be clamped. When the abrading wheel is retracted from the cutter H) as far as the boss 15 will permit, the flange 71 is seated on the boss, as shown in the drawing, and the friction, due to this engagement, is effective to arrest rotation of the abrading wheel, the 55 spindle I3 and all the other parts included in the' arranged to be engaged by a corresponding surface at the upper end of a sleeve 16 which constitutes the driven member of the clutch. The

driving member 22 has no freedom to move up and down but the driven member 16 is capable of axial movement toward and from it for clutching and declutching purposes. Moreover, the driven member has a spline connection with the spindle 13 for imparting rotation thereto and to enable the spindle to move up and down when such movement of the member 16 is arrested as by engagement with the driving member 22. The spline connection between the member 16 and the spindle is provided by a collar 84 pinned to the spindle and having a key portion that projects into a key-way extending axially in the bore of the member 16.

The lower end of the member 16 is seated on the upper end of the bushing 14 which not only provides a bearing for the spindle but also constitutes one element of a clutch-operating mechanism. For the latter purpose the upper end of this bushing is provided with a flange in which sockets are formed for the reception of the upper ends of three compression springs 82 (Fig. 2) that tend constantly to raise the driven member 16 into engagement with the driving member 22 with a force suflicient for driving the wheel 21 but inferior to the force of gravity by which the spindle l3 and the elements supported thereby are normally retracted from the cutter I8. Rotation of the bushing 14 is prevented by a screw 83 secured in the bracket SI and having a smooth upper end that projects into a hole bored in the flange of the bushing.

A hand lever 69 is provided for raising the abrading wheel 2l to its operative position in contact with the cutter [0. The lever 69- is conpreferably supplemented by the force of a tension spring 92 connected to the lever 69 to insure declutching the driven member 16 and a considerable braking pressure of the flange 11 against the boss 15.

The operation of the described assemblage is as follows: Assuming that the cutter l0 and the pulley 22 are both in rotation and that the abrading wheel 2| is out of rotation, as when the parts are in their initial'positions, as shown, upward movement of the handle portion of the lever 69 will raise the spindle I3 and the abrading wheel, thus removing nearly all the load from the light compression springs 82. The only portionof the load that remains on these springs is that tijoi the bushing 14 and the driven member 16 o'f""'the clutch. Under these conditions, the driven member 16 is shifted to its operative position, not by the spindle 13, but by the combined forces of the springs 82, and the-driving eifect of the clutch begins when the upper surface of member 22 the spline member 84 travels along the bore and the key-way of the member 18.

A screw 85 adjustably secured in the free end of a stiff leaf-spring 86 is arranged in the path of a portion of the hand-lever 69 to be engaged and displaced by the final lifting movement of the lever after the clutch begins to operate. The leaf-spring 86 is anchored to the frame [8. In operation, this resilient abutment arrests the .travel or the rotary abrading assemblage toward its operating position when the abrading Wheel is almost, but not quite, in contact with the cutter 18. The brief stoppage of this travel prevents the abrading wheel from striking the cutter with a sudden impact, prolongs the interval in which the clutch may speed up the rotation of the abrading wheel, and warns the user, through the sense of touch, that only a slight additional movement is required to complete the travel of the abrading wheel to its operating position. The user may then apply enough additional effort to overcome the resistance of the spring 86. When the combined forces of gravity and the spring 92 are permitted to retract the abrading wheel, the collar 84 retracts the driven member 16 against the inferior force of the springs 82 until finally the flange 11 becomes seated on the boss '15, whereupon the retractor movement is positively arrested and the braking pressure ap plied to arrest rotation of the abrading wheel.

The invention also provides for utilizing the described clutch and clutch-operating mechanism in combination with a supplemental device for dressing the operating surface of the abrading wheel. This device comprises a dressing tool 88 anda manually movable holder 89 in which .the tool is secured. If desired, the lower end of the tool 88 may be provided with a diamond for dressing the abrading wheel. The holder 89 includes a clamping plate 98 and a clamping screw 99 and provides for adjusting the tool 88 lengthwise to place its lower end at the desired level, which should be only slightly above the level of the broken line AA when the dressing device is in its operative position. The holder 89 is mounted on the bracket 8| to which it is connected by a pivot pin 90. The holder is normally maintained in an inoperative position by the first move the holder as with the left hand to place the tool 88 over the abrading wheel 2|, the screw 91 serving then to arrest the tool when it is in register with the inner boundary of the operating surface of the abrading wheel. With the right hand the operator will raise the handle portion of the lever 69 to connect the abrading wheel with its source of rotation and at the same time to raise it into engagement with the tool 88, the total range of elevation of the abrading wheel under these conditions being little more than enough to set the clutch in operation but not enough to carry the abrading wheel into engagement with the cutter Ill. While the operators right hand continues to maintain the abrading wheel in contact with the tool 88, the holder 89 may be rocked backward and forward with short strokes until the operating surface of the wheel has been dressed. All the. parts will return automatically to their initial positions when released.

For certain purposes set forth in the aforesaid Meyer application, the axis of the abrading wheel may be exactly parallel with that of the cutter ill, but it is sometimes desired to tilt the axis of the abrading wheel to the left for the purpose of grinding a hollow or concave surface on the bottom of the cutter. Accordingly, the bracket 8| is mounted to provide for such tilting, and the described organization is such that the several mechanisms concerned with the operation and control of the abrading wheel 2| all partake alike of the adjustment movements of the bracket 8| without disturbance of their co-operative relations.

The bracket BI is secured to a portion of the frame l8 by two cap-screws 93 and 94, which, when set up tightly, clamp the bracket firmly to the frame. The axis of the screw 93 is the axis about which the bracket may be adjusted to tilt the abrading wheel or to place its operating surface in parallel relation to the plane of the cutting edge l2. On the other hand, the shank of the screw 94 extends through a hole in the frame l8 that is considerably larger than the shank and provides limited range of adjusting movement. The screw-threads of both screws 93 and 94 engage corresponding screw-threads in the bracket 8!. Moreover, the axis of the screw 93 is arranged to intersect that portion of the belt 20 that runs on the pulley 22. This relation avoids disturbance of the co-operative relation of the belt and the pulley when the bracket 8| is adjusted within the limits afforded by the screw 94.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent of the United States is:

l. A combination comprising a rotary assemblage so mounted as to be movable to and from an operating position and including a member for operating on a Work-piece, manually operable means arranged to shift said assemblage from a retractive position to its operative position, means arranged to impart rotation to said assemblage, and a resilient abutment arranged to be encountered initially at an intermediate point in the travel of said assemblage to its operative position and to be deflected by supplemental manual effort applied to said manually operable means to complete such travel.

2. A combination comprising an assemblage so mounted as to be movable manually to and from an operating position and including a rotary member for operating on a work-piece, a clutch having a driving member and a driven member arranged to impart rotation to said rotary member and to be operatively coupled by movement of said assemblage at an intermediate point in its range of travel toward said operating position, and a resilient abutment arranged to be encountered by said assemblage initially at an intermediate point in its travel toward said operating position where said rotary member will be almost but not quite in contact with the workpiece and to arrest such travel at that point but to yield under supplemental force exerted in a direction to shift said rotary member into contact with the work-piece.

3. A combination comprising a rotary workholder having a pulley, bearing means in which said work-holder is journaled, a rotary and axially movable shaft and a member secured thereto for operating on a work-piece secured to said holder, bearing means in which said shaft is journaled, a clutch having a driving member and a driven member both surrounding said shaft, the driving member being rotatable with respect to the shaft but the driven member being keyed to the shaft, and a power-driven belt one portion of which is arranged to operate on a segment of said pulley and another portion of which is arranged to operate on a segment of the driving member of said clutch.

ROBERT N. SANDBERG. 

